Alien Life: Diversity in the Universe

Despite all the profusion of life on Earth, we have so far only found the descendants of a single ancient cell. All the life that we know shares its basis in the carbon chemistry of nucleic acids, amino acids and proteins. All of it – however extreme its environment - needs water to function.

In the first two sessions of Discuss 2018, we will ask what, and where, life can exist. Could the subsurface oceans of Enceladus or Europa support life based on similar chemistry to Earth’s? Could Titan host “exotic life”? And what about planets and moons beyond our solar system? Is it time to widen the habitable zone as traditionally conceived, as well as to take seriously the possibility of life-forms based on substrates and solvents beyond carbon and water – including artificial machines?

Human life has exploded the pace of innovation in nature, developing new forms of structure in which to live, produce and travel. In the final session, we will look at new possibilities for space travel, and what they could tell us about technological life in the Universe – our own and perhaps others’.

Session One

Search for Life in our Solar System

Chairs: Penelope Boston, Chris McKay

In recent years, the search for life in Earth’s local neighborhood has shifted to “ocean worlds” in the outer solar system, particularly Europa and Enceladus. Attention centers on Saturn’s moon Enceladus – where organic-rich water plumes jet into space. Such ocean material is potentially accessible to space probes. Jupiter’s moon Europa and other possible locations may also exhibit water ejections and could have evidence of life on their surface. Other locations, such as Saturn’s moon Titan with its hydrocarbon lakes, could potentially host exotic life based on very different chemistry from our own. What would a mission to these targets look like? And what sensors would such a probe need to carry?

Session Two

Possibilities for Non-Terran Life in the Universe

Chairs: Svetlana Berdyugina, Lisa Kaltenegger

How do we define life? And how do we search for life-forms that could be very different from our own? Exotic environments, such as Titan’s hydrocarbon lakes, raise the question of whether life could arist based on alternate chemical substrates. If life exists on Earth-size planets in the “habitable zones” of red dwarfs, such as those recently discovered around Proxima Centauri and Trappist One, it may have to rely on such alternate chemistries, since the light spectrum and radiation environments are very different than those on earth. Even further afield, it has been suggested that machine-based intelligences could exist far from any star. Could we detect such alien “life-forms”?

Session Three

Progress in Novel Space Propulsion

Chairs: Sigrid Close, Zachary Manchester

To extend humanity’s reach beyond our solar system, novel means of propulsion are needed. Light-sails, directed-energy, and antimatter have all been proposed as ways of meeting the extreme challenges of interstellar travel. What is the ‘state of the art’ in space propulsion? How close are we to achieving the dream of traveling to our nearest neighboring stars within a human’s lifetime? And can innovative propulsion technologies enable new means for the search for life in our solar system, or for non-Terran life in the Universe?